Molded pulp carton latch



Nov. 2, 1965 u. H. DESPRES 3,

MOLDED PULP CARTON LATCH Filed Nov. 20, 1963 2 Sheets-Sheet 1 INVENTOR4h ATTORNEYS U. H. DESPRES MOLDED PULP CARTON LATCH 2 Sheets-Sheet 2INVENTOR Urban Hfiasjaras BY Z ATTORNEYS Nov. 2, 1965 Filed Nov. 20,1965 United States Patent 3,215,326 MOLDED PULP CARTON LATCH Urban H.Despres, Clinton, Maine, assignor to Keyes Fibre Company, Portland,Maine, a corporation of Maine Filed Nov. 20, 1963, Ser. No. 324,950 13Claims. (Cl. 229-2.5)

This invention relates to a molded pulp container, and more particularlyto improved provisions for latching such cartons in closed condition.

Prior molded pulp containers are subject to various disadvantagesconcerning mechanism for latching the carton in the closed position. Forinstance, previous latches of the snap-lock variety, as opposed to thetuck-in friction flap variety, are fairly awkward to manipulate forunlatching the carton. Others, constructed along less awkward lines,have proved relatively ineflicient in that they do not securely hold thecarton in the closed position, and frequently involve protruding lugelements which occasionally interfere with efiicient stagger stacking ofthe cartons in standard size shipping containers. Other designs, whileperhaps more efficient and less awkward, have proved relativelydiflicult and expensive to form by means of standard pulp moldingprocesses. A prior latch is illustrated in Reifers 2,990,094.

The latches on molded pulp cartons for eggs or other fragile articles,moreover, must be capable of being latched by machine and unlatched bythe housewife or other consumer without damaging the eggs. A latch whichrequires that a flap or other member be pushed inwardly more than a veryslight distance is thus undesirable, since the greater the inward pushrequired the greater the chance of breakage to the carton contents.Also, since such cartons, for obvious commercial reasons, are made nolarger than necessary to enclose a desired grade of eggs, the amount ofspace required for operation of a latch mechanism becomes important.

Additionally, molded pulp egg cartons, especially of the type which donot have egg pockets molded in the cover or lid, are subject to someflexibility of the depending front wall of the lid. Since latches arefrequently located at least in part on this front wall, the problem ofproviding an easily unlatchable device that will not accidentally comeopen is increased as the flexibility of the carton is increased.

Accordingly, it is an object of the present invention to provide amolded pulp container of the type including bottom and top membershaving latch means for securing them in the closed position whichobviates the above problems.

Another object of the present invention is to provide a molded pulpcontainer wherein the latch means for maintaining the top and bottom ofthe container in the closed position includes cooperating bridge meansto hold the container closed as well as detent means to maintain thebridge means in engagement.

Another object of the present invention is to provide an egg cartonlatch which occupies only a single thickness of molded pulp which may bequickly and economically molded according to known pulp moldingprocesses.

Other features and advantages of the present invention will becomeapparent to one skilled in the art from a reading of the followingdescription in conjunction with the accompanying drawings whereinsimilar reference characters refer to similar parts, and in which:

FIG. 1 is a plan view of the preferred embodiment of molded pulpcontainer in the fully opened position;

FIG. 2 is a front elevational view of the container of FIG. 1 in thefully closed position;

FIG. 3 is a front elevational view of the container of FIG. 1 in apartly closed position;

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FIG. 4 is a sectional view on line 4-4 of FIG. 3 showing further detailsof the latch mechanism;

FIG. 5 is a sectional view on line 5-5 of FIG. 2 showing details of thelatch mechanism in the closed position;

FIG. 6 is a sectional view corresponding to FIG. 4 showing amodification of the latch means of this invention; and

FIG. 7 is a sectional view corresponding to FIG. 5 showing the modifiedlatch mechanism in the closed position.

Referring to the drawings, the latch mechanism of this invention may beincorporated in any variety of molded pulp carton having at least twoportions such as a top and bottom portion which come together to aclosed position. For instance, the embodiments illustrated in thedrawings involve a molded pulp carton 10 for holding fragile articles,such as eggs, which has a containing or bottom section 12, a lid or topsection 14 hinged at 16 to one side of the bottom, and a locking flapmeans 18 hinged at 20 to the other side of the bottom.

The bottom 12 may be formed with a plurality of article holding pockets22 and article spacing posts 24 integrally molded therein. Each fullpost 24 is provided with four laterally extending ribs 26, each ribbeing offset from the adjacent rib, and is surrounded by the fourpockets 22, in a well known manner. The bottom 12, as can be seen fromthe drawings, has an upstanding wall 28 around the edge, the uppersurface of which occupies a relatively fiat plane. Peripherallypositioned half posts 29 form an integral part of the wall 28.

The top or lid 14 may be formed with a flat body portion 30 and adepending wall 32 therearound having a depth generally comparable to thedepth of the bottom wall 28. The lower surface of the wall 32 alsooccupies a relatively flat plane, and is of a shape and size to rest onthe upper surface of the lower wall 28 when the container is closed. Aplurality of inwardly extending vertical buttress ribs 34 may be formedintegrally with the wall 32 of the top to provide additional strength.Two such ribs are located on the depending front wall of the cover, andeach includes a flat base or Web portion 35 generally parallel with thefront wall of the cover and joined thereto by side portions 36. The webportion 35 joins with the base or top 30 of the cover 14. Each rib is ofsubstantially uniform depth throughout its height, and tapers narrowertoward the bottom in width. Either the top, the bottom, or both may beprovided with perforations for ventilation or other purposes, ifdesired.

The locking flap means 18 may comprise a marginal tab of a widthsomewhat less than the depth of the top wall 32. The locking flap ismolded in the open position, and thus retains a resilient characteristicat its hinge 20 which normally biases it in an outward direction againstthe inside of the front wall of the top.

The latching means according to this invention comprises two portions.One portion includes an opening 38 in the locking flap 18. In thedrawings, two such openings are shown, one opposite each of the twobuttress ribs 34 on the front wall of the cover. Each opening 38 may bereferred to as a bridge-receiving cavity, and each extends from a pointintermediate the top and bottom of the locking flap to the inner edge ofthe flap adjacent the hinge 20, and is of a width which is greater thanthe lower narrow portion of the buttress ribs of the cover front wall.

The other portion of the latch means includes a somewhat similar opening40 located in an inwardly extending vertical buttress rib 34 of thefront wall 32 of the top. Again, two such openings 40 may be provided,one in each of the two buttress ribs in the front wall of the top. Eachopening 40 may also be referred to as a bridgereceiving cavity, and eachbegins at a point intermediate the top and bottom of the top wall 32 andextends downwardly a short distance which does not carry it all the wayto the bottom margin of the wall 32. The width of each cavity 40,however, is sufficient to carry it across the flat web 35 andsignificantly into the sloping side walls 36 of the buttress rib.

The portion of the locking flap outside or above the bridge-receivingcavity 38 may be referred to as a bridge 42, and is relatively flat,lying in the same general plane as the rest of the locking flap. Theportion of the top wall buttress rib outside or below thebridge-receiving cavity 40 may also be referred to as a bridge 44, andis somewhat curved or inwardly protruding because of following theinward curve of the buttress rib out of the general plane of the rest ofthe front cover wall. The two bridges 42, 44 of each portion of thelatch means are adapted to be received within the bridge-receivingcavity of the other portion so that the bridges encounter each otherwith a laterally adjacent engagement to latch the top or lid 14 to thelocking flap 18. In the closed or latched position, the inwardlyprotruding bridge 44- latches beneath the relatively flat bridge 42;that is, the flat bridge 42 of the resilient flap is urged outwardlyinto the cavity 40.

While the modified embodiment illustrated in FIGS. 6 and 7 comprises theabove described structure identified by similar reference numerals withthe addition of a prime mark the preferred embodiment illustrated inFIGS. lmay further include detent means for securing the front Wall ofthe cover against outward flexing to preclude inadvertant unlatching ofthe carton. The detent means includes a protrusion 46 on each of the twobuttress ribs 34 on the front of the wall 32 of the top 14. Each suchprotrusion, as best seen in FIG. 4, may be integrally molded with thebottom of each rib 34 to extend downwardly in depending fashion belowthe bot tom plane of the wall 32 of the top 14. The detent means furtherincludes a mating aperture 48 at the base or hinge edge of the lockingflap 18. These apertures, as seen from the drawings, may conveniently beformed as the lower parts of the bridge-receiving cavities 38 to securethe detents 46 inside the upper margin of the front portion of theupstanding wall 28 of the carton bottom 12.

As seen from FIG. 5, it will be clear that the protrusion 46 passesthrough the mating aperture 48 when the container is closed to preventthe mid-portion of the front wall 32 of the .top 14 from swinging orflexing outwardly beyond the lateral boundaries of the more rigidupstanding wall 28 of the pocketed bottom 12. The locking flap 18 isresiliently hinged at 20 in a manner which normally tends to .swing theflap 18 outwardly against the inside of the wall 32 of the top. It willbe clear that the detent means comprising cooperating protrusions andapertures may be formed with buttress ribs-other than the two whichcontain the latch means if such are provided on the front wall of thecover with mating ribs at corresponding places on the locking flap toallow engagement of the bridge means; likewise, .it will be clear that,depending upon the size and shape of the container, a larger or fewernumber of latch means and a larger or fewer number of detent means maybe provided either in the same or different buttress ribs.

In use, when .the container has been filled with eggs, the locking flap18 is folded inwardly and the top 14 is swung .thereover to a closedposition wherein the top wall 32 and bottom wall 28 come together. Asthe container is closed, the protrusion 46 of the detent means wedges inthe aperture 48 behind the upper margin of the bottom front wall wherethe flap 18 is hinged, and thus retains the front of the top wall 32inwardly. This insures that the bridges 42 and 44 will interlock,because the inherent resiliency of the flap hinge urges the inwardlyprotruding bridge 44 of the top into the bridge-receiving cavity 38 ofthe flap 18 attached to the bottom, and the bridge 42 of .the flap intothe larger cavity 40 of the top. As

the two bridges of each locking means thus overlap, the top 14 issecured against opening, and the container is ready for packing inshipping crates.

Upon receipt of the filled container by the consumer, the container ofthis invention is easily unlocked by manually depressing the bridges 42through the cavities 48 only slightly inwardly while lifting the top 14slightly outwardly and upwardly to expose the contents of the container.

It will be noted that the locking flap 18 is shown as an essentiallyplanar member parallel to the line of the upper rim of the front wall 28of .the carton bottom. As seen in FIGS. 5 and 7, the buttress rib on thecover which prevents the flap bridge 42, 42 from extending clear throughto the outside of the cover front Wall also prevents the flap 18 fromlying completely flat against the inside of the cover front wall. Sincethe latch means are located between egg pockets, the flap may be flexedoutwardly into contact with the inside of the cover front wall by eggsin the pockets in the areas between and beyond the latch means. Asidefrom providing an egg cushioning feature, this further insures againstaccidental unlatching. If desired, of course, such flap flexing may beanticipated in design by providing inwardly depressed contours in thenature of vertical nesting buttress ribs on the flap in the areas of thelatch means.

Thus, a molded pulp container has been disclosed which provides anextremely efiicient latching means Which is inexpensive to manufactureaccording to current pulp molding processes, and which may be readilyadapted to current carton closing machinery. Moreover, the latchingmeans, whether with or without the latch securing detent means, issusceptible of quick and easy opening by the consumer, and thepossibility of egg breakage is minimized because no significant inwardmotionof any member is required for unlatching. Finally, the extremesimplicity of the latch means of this invention is strictly confined toa single thickness of pulp material within the normal contours of thecontainer, and is thus adapted for inexpensive manufacture not requiringformation of thickened, critically dimensioned lugs or protrusions.

While the above described embodiments constitute preferred modes ofcarrying out this invention, other rnodifications and equivalents may beresorted to within the scope of the actual invention, which is claimedas follows.

What is claimed is:

1. A molded pulp container comprising a pair of members, at least one ofwhich has a wall formed thereon, forming a bottom and a closable top,locking flap means attached to the other member and designed to bereceived generally against and inside the opposed wall of the one memberwhen the pair of members are in a closed position, means urging the flapmeans against the inside of the opposed wall when the pair of membersare in a closed position, latch means comprising two portions, one onthe locking flap means and the other on the opposed wall of the onemember, each portion including a bridge and a bridge-receiving cavityvertically adjacent each other, the bridge on the opposed wallprotruding inwardly of the container and the bridge on the locking flapmeans being formed so as not to protrude outwardly so that the bridge ofeach portion is received within the cavity of the other portion wherebythe bridges engage to latch the pair of members in the closed position.

2. A molded pulp container comprising a pair of members, at least one ofwhich has a wall formed thereon, forming a bottom and a closable top,locking flap means attached to the other member and designed to bereceived generally against and inside the opposed wall of the one memberwhen the pair of members are in a closed position, means urging the flapmeans against the inside of the opposed wall when the pair of membersare in a closed position, a buttress rib on the opposed wall of the onemember, latch means comprising two portions, one on the locking flapmeans and the other on the buttress rib, each portion including a bridgeand a bridge-receiving cavity vertically adjacent each other so that thebridge of each portion is received within the cavity of the otherportion whereby the bridges engage to latch the pair of members in theclosed position.

3. A molded pulp container as in claim 2 wherein the bridge-receivingcavity on at least the buttress rib of the wall comprises an openingextending entirely through the Wall whereby the bridge of the lockingflap means may be manually depressed inwardly to unlatch the container.

4. A molded pulp container comprising a pair of members, at least one ofwhich has a wall formed thereon, forming a bottom and a closa-ble top,locking flap means attached to the other member and designed to bereceived generally against and inside the opposed wall of the one memberwhen the pair of members are in a closed position, means urging the flapmeans against the inside of the opposed wall when the pair of membersare in a closed position, detent means for securing the opposed wall ofthe one member adjacent the locking flap means when the pair of membersare in the closed position, latch means comprising two portions, one onthe locking flap means and the other on the opposed wall of the onemember, each portion including a bridge and a bridge-receiving cavityvertically adjacent each other, the bridge on the opposed wallprotruding inwardly of the container and the bridge on the locking flapmeans being formed so as not to protrude outwardly so that the bridge ofeach portion is received within the cavity of the other portion wherebythe bridges engage to latch the pair of members in the closed position.

5. A molded pulp container of generally similar thickness throughoutcomprising a pair of members, at least one of which has a wall formedthereon, forming a bottom and a closable top, locking flap meansattached to the other member and designed to be received generallyagainst and inside the opposed wall of the one member when the pair ofmembers are in a closed positions, means urging the flap means againstthe inside of the opposed wall when the pair of members are in a closedposition, detent means for securing the opposed wall of the one memberadjacent the locking flap means when the pair of members are in theclosed position, an inwardly extending buttress rib on the opposed wallof the one member, lat-ch means comprising two portions, one on thelocking flap means and the other on the buttress rib, each portionincluding a bridge and a bridge-receiving cavity vertically adjacenteach other so that the bridge of each portion is received within thecavity of the other portion whereby the bridges engage to latch the pairof members in the closed position.

6. A molded pulp container as in claim 5 wherein the detent meanscomprises a protrusion on the buttress rib of the wall and a matingaperture formed as part of the bridge-receiving cavity of the lockingflap means.

7. A molded pulp container comprising a bottom mem ber includingupstanding front and rear walls and rib means connected between thewalls to define a plurality of article receiving pockets as well asimpart rigidity to the walls, a cover member including depending frontand rear walls, the lower edge of the cover member rear wall and theupper edge of the bottom member rear wall being integrally hingedtogether, a locking flap integrally hinged to the upper edge of thebottom member front wall and designed to be received generally againstand inside the cover member front wall when the cover member is in theclosed position, latch means comprising a bridge-re ceiving cavity inthe locking flap and a vertically adjacent bridge formed on the lockingflap, so as not to protrude outwardly of the general plane thereof, abridge-receiving aperture and a vertically adjacent bridge formed on thecover member front wall, the bridge-receiving aperture being adapted toreceive the locking flap bridge when the cover member is in the closedposition, the cover member bridge protruding inwardly of the covermember front wall to be received by the locking flap cavity and beneaththe locking flap bridge when the cover member is in the closed positionwhereby the bridges engage each other to latch the cover member in theclosed position and the cover member aperture permits manual inwarddepression of the locking flap bridge to unlatch the container.

8. A molded pulp container as in claim 7 wherein the locking flapbridge-receiving cavity comprises an opening extending entirely throughthe locking flap.

9. A molded pulp container as in claim 7 wherein the locking edge of thelocking flap bridge lies essentially in the general plane of the lockingflap and parallel with the locking flap hinge.

10. A molded pulp container as in claim 7 wherein the width of thelocking flap is smaller than the height of the cover member front wall,and at least the cover member rear wall includes vertically disposedbuttress ribs.

11. A molded pulp container as in claim 7 wherein the lower edge of thecover member front wall is adapted to overlie the locking flap hingewhen the cover member is in the closed position.

12. A molded pulp container as in claim 11 wherein the lower edge of thecover member front wall includes a depending detent protrusion and thelocking flap includes a cooperating detent cavity adjacent its hinge tosecure the cover member front wall against outward flexing and adjacentthe locking flap when the cover member is in the closed position.

13. A molded pulp container as in claim 12 wherein the locking flapbridge-receiving cavity and the locking flap detent cavity are formed asparts of a single opening extending entirely through the locking flap,and the cover member bridge and the cover member detent protrusion arepart of a single inwardly and downwardly extending formation.

References Cited by the Examiner UNITED STATES PATENTS 2,578,739 12/51Randall 2292.5 2,843,304 7/58 Reifers 229 45 2,974,842 3/61 Reifers2292.5 3,144,973 8/64 Heintzelman 2292.5

JOSEPH R. LECLAIR, Primary Examiner.

FRANKLIN T. GARRETT, Examiner.

1. A MOLDED PULP CONTAINER COMPRISING A PAIR OF MEMBERS, AT LEAST ONE OFWHICH HAS A WALL FORMED THEREON, FORMING A BOTTOM AND A CLOSABLE TOP,LOCKING FLAP MEANS ATTACHED TO THE OTHER MEMBER AND DESIGNED TO BERECEIVED GENERALLY AGAINST AND INSIDE THE OPPOSED WALL OF THE ONE MEMBERWHEN THE PAIR OF MEMBERS ARE IN A CLOSED POSITION, MEANS URGING THE FLAPMEANS AGAINST THE INSIDE OF THE OPPOSED WALL WHEN THE PAIR OF MEMBERSARE IN A CLOSED POSITION, LATCH MEANS COMPRISING TWO PORTIONS, ONE ONTHE LOCKING FLAP MEANS AND THE OTHER ON THE OPPOSED WALL OF THE ONEMEMBER, EACH PORTION INCLUDING A BRIDGE AND A BRIDGE-RECEIVING CAVITYVERTICALLY ADJACENT EACH OTHER, THE BRIDGE ON THE OPPOSED WALLPROTRUDING INWARDLY OF THE CONTAINER AND THE BRIDGE ON THE LOCKING FLAPMEANS BEING FORMED SO AS NOT TO PROTRUDE OUTWARDLY SO THAT THE BRIDGE OFEACH PORTION IS RECEIVED WITHIN THE CAVITY OF THE OTHER PORTION WHEREBYTHE BRIDGES ENGAGE TO LATCH THE PAIR OF MEMBERS IN THE CLOSED POSITION.